Recently, several technologies that provide broadband data access have entered the market. These technologies include digital subscriber lines (DSL), cable modems, and wireless networks, among others. Another emerging technology uses existing electrical power distribution networks to carry data signals to and from individual customer premises. Such systems may be referred to throughout as “power line communication systems.” Because electrical power distribution networks have been designed to carry low-frequency high-voltage signals, transmitting higher frequency data signals on the electrical power distribution network often face obstacles not confronted by their lower frequency counterparts.
One particular impediment is not a part of the network of low voltage cables originally installed. This impediment may be created by devices and appliances that are “plugged into” the low voltage premise network. These devices will be referred to as “power line non-communication devices,” because traditionally they receive power and do not exchange data over the premise network. “Power line communication devices,” on the other hand, refer to devices designed to communicate with higher frequency data signals, like modems and computing devices, over the premise network. Because the low voltage premise network originally was not created to carry and process higher frequency data signals, the traditional power line non-communication devices were created without concern of their effect on such higher frequency data signals. In fact, often many of the non-communication devices that typically plug into electrical receptacles connected to the low voltage premise network have certain components that will attenuate or “load down” higher frequency signals.
For example, many existing power line non-communication devices have decoupling capacitors. The decoupling capacitors have the beneficial effect of filtering high frequency signals or “noise” from adversely influencing the operation of the device. These decoupling capacitors typically have capacitance values in the range of 0.1 to 0.22 μF, but may have any value. The decoupling capacitors prevent the noise from influencing the device by severely reducing the high frequency signal content from entering the operational portion of the device. For example, these filtering devices are used to keep the operation of a household blender from adversely influencing a television's picture. It should be appreciated that a decoupling capacitor is just one such device that may cause such a problem in a power line communication system.
Although this solution has been effective for its intended purpose of filtering noise, it now has the unintended effect of attenuating the high frequency data signals communicated over the low voltage network. As a result, the ability of the low voltage premise network to operate as a high frequency data network is compromised.
Therefore, there is a need to reduce the loss of the higher frequency data signals transmitted on the low voltage home premise without effecting the 50/60 Hz power signal traditionally delivered on the network.